scholarly journals Adhesive defence mucus secretions in the red triangle slug (Triboniophorus graeffei) can incapacitate adult frogs

2019 ◽  
Author(s):  
John Gould ◽  
Jose W. Valdez ◽  
Rose Upton
Keyword(s):  
Dorsal Surface ◽  
Biomechanical Properties ◽  
Natural World ◽  
Tree Frog ◽  
Field Observations ◽  
Defensive Secretions ◽  
Mucus Production ◽  
Laboratory Conditions ◽  
Adhesive Materials ◽  
Stimulation Of

AbstractGastropods are known to secrete mucus for a variety of purposes, including locomotion, reproduction, adhesion to surfaces, and lubrication. A less commonly known function of mucus secretion in this group involves its use as a defence against predation. Among the terrestrial slugs, mucus that serves this particular purpose has been studied for only a handful of species under laboratory conditions, where it is thought to be produced for self-fouling or to make individuals difficult to consume. However, the mechanisms of how these defensive secretions operate and their effectiveness in deterring predation in the natural world have not be described in much detail. In this study, we provide evidence of adhesive mucus secretions in the red triangle slug (Triboniophorus graeffei) as an adaptation against predation. Field observations of a large red-eyed green tree frog (Litoria chloris) trapped in the mucus secretions of a nearby T. graeffei revealed that this mucus serves to incapacitate predators rather than just simply as an overall deterrence. Mechanical stimulation of T. graeffei under laboratory conditions revealed that adhesive secretions were produced from discrete sections of the dorsal surface when disturbed, leading to the production of a highly sticky and elastic mucus that was unlike the thin and slippery mucus used during locomotion. The adhesiveness of the defensive secretions was strengthened and reactivated when in contact with water. This appears to not only be the first description of defensive mucus production in this slug species but one of the first natural observations of the use of adhesive defence secretions to incapacitate a predator. The biomechanical properties of this mucus and its ability to maintain and strengthen its hold under wet conditions make it potentially useful in the development of new adhesive materials.

Identification of Mechanoafferent Neurons in Terrestrial Snail: Response Properties and Synaptic Connections

2002 ◽  
Vol 87 (5) ◽  
pp. 2364-2371 ◽  
Author(s):  
Aleksey Y. Malyshev ◽  
Pavel M. Balaban
Keyword(s):  
Avoidance Behavior ◽  
Receptive Fields ◽  
Dorsal Surface ◽  
Mechanical Stimulus ◽  
Terrestrial Snail ◽  
Mechanosensory Neurons ◽  
Intracellular Stimulation ◽  
Pleural Ganglion ◽  
Withdrawal Response ◽  
Stimulation Of

In this study, we describe the putative mechanosensory neurons, which are involved in the control of avoidance behavior of the terrestrial snail Helix lucorum. These neurons, which were termed pleural ventrolateral (PlVL) neurons, mediated part of the withdrawal response of the animal via activation of the withdrawal interneurons. Between 15 and 30 pleural mechanosensory neurons were located on the ventrolateral side of each pleural ganglion. Intracellular injection of neurobiotin revealed that all PlVL neurons sent their axons into the skin nerves. The PlVL neurons had no spontaneous spike activity or fast synaptic potentials. In the reduced “CNS-foot” preparations, mechanical stimulation of the skin covering the dorsal surface of the foot elicited spikes in the PlVL neurons without any noticeable prepotential activity. Mechanical stimulus-induced action potentials in these cells persisted in the presence of high-Mg2+/zero-Ca2+ saline. Each neuron had oval-shaped receptive field 5–20 mm in length located on the dorsal surface of the foot. Partial overlapping of the receptive fields of different neurons was observed. Intracellular stimulation of the PlVL neurons produced excitatory inputs to the parietal and pleural withdrawal interneurons, which are known to control avoidance behavior. The excitatory postsynaptic potentials (EPSPs) in the withdrawal interneurons were induced in 1:1 ratio to the PlVL neuron spikes, and spike-EPSP latency was short and highly stable. These EPSPs also persisted in the high-Mg2+/high-Ca2+ saline, suggesting monosynaptic connections. All these data suggest that PlVL cells were the primary mechanosensory neurons.

Stimulation of Mucus Production

Sucralfate ◽  
1995 ◽  
pp. 83-88
Author(s):  
Clifford Tasman-Jones
Keyword(s):  
Mucus Production ◽  
Stimulation Of

scholarly journals The Anatomy of the Dorsal Capsulo-Scapholunate Septum: A Cadaveric Study

2017 ◽  
Vol 06 (03) ◽  
pp. 244-247 ◽  
Author(s):  
Marina Tommasini Carrara de Sambuy ◽  
Tanya Burgess ◽  
Christophe Mathoulin ◽  
Adeline Cambon-Binder
Keyword(s):  
Dorsal Surface ◽  
Anatomical Study ◽  
Biomechanical Properties ◽  
Scapholunate Ligament ◽  
Maximum Width ◽  
Interosseous Ligament ◽  
Gothic Architecture ◽  
Constant Structure ◽  
Fresh Frozen ◽  
The Mean

Background Tears of the dorsal radiocarpal capsule at the level of the scapholunate interosseous ligament (SLIL) have recently been described in association with predynamic scapholunate instability. Purpose The aim of this anatomical study of the dorsal capsulo-scapholunate septum (DCSS) was to examine the connection of the dorsal capsule on the SLIL and dorsal intercarpal ligament (DICL). Methods Fourteen fresh frozen wrists from seven adult cadavers were dissected through a dorsal approach. Any dorsal attachment of the DICL on the dorsal surface of the SLIL, that is, the DCSS, was identified and measured (height and width). Results The DCSS was consistently found connecting the DICL, the dorsal radiocarpal capsule, and the dorsal aspect of the SLIL. It was formed by the confluence of three arches like intersecting ribs in gothic architecture. The mean dimensions of the DCSS were 5.8 mm in height and 4.0 mm in maximum width. Conclusion The DCSS that connects the SLIL with the dorsal capsule and DICL could be a constant structure of dorsal wrist. Further investigation is required to study the histology of the DCSS and its biomechanical properties in isolation to know whether the DCSS can be considered a secondary stabilizer of the scapholunate ligament complex. Clinical Relevance A better anatomical knowledge of scapholunate ligament complex could help understand and manage instability of the wrist.

scholarly journals Overproduction of gastric mucus as a mechanism of stomach’s mucosa protection during energy drinks consumption in Wistar rats

2018 ◽  
Vol 72 ◽  
pp. 376-380
Author(s):  
Ruby Maini ◽  
Ewelina Wawryk-Gawda ◽  
Mirosław Sławiński ◽  
Paweł Halczuk ◽  
Beata Cichacz-Kwiatkowska ◽  
...  
Keyword(s):  
Wistar Rats ◽  
Energy Drinks ◽  
Energy Drink ◽  
The Body ◽  
Gastric Mucus ◽  
Gastric Glands ◽  
Mucus Production ◽  
The Impact ◽  
Stimulation Of

Aim: Energy drinks are the most consumed, socially accepted stimulants in the world. They are drunk by drivers and students, and more often also by adolescents and children. It has been noted that some adverse events are due to the stimulation of the sympathetic nervous system and include palpitations, hypertension, diuresis, nausea, vomiting, and convulsions. The health consequences of long-term consumption of energy drinks are not known, but we suppose that continuous stimulation of the body can lead to irreparable changes of tissues. In our study we investigated the impact of long-term energy drink consumption on gastric mucus production. Material/Methods: Ten male young Wistar rats of of 190 grams +/- 64 grams of weight were positioned in two groups: A (experimental) and C (control). The animals of A group received energy drink for 8 weeks. The animals of C group drank just water. After this time the rats of both groups were decapitated and the stomach was taken for histological analysis. The slides were stained with H&E and PAS method and analyzed with Cell^D software. Results: H&E staining indicated an increase in the thickness of the lamina propria of the glandular stomach. PAS staining indicated an increased area of mucus in the gastric glands of the stomach of the experimental group of rats. Conclusions: Regular consumption of energy drinks can lead to changes in the mucosal lining of the stomach, which activate mucus secretion.

scholarly journals Evaluation of tree frog tracking methods using Phyllomedusa trinitatis (Anura: Phyllomedusidae)

2018 ◽  
Vol 17 (2) ◽  
pp. 233-246 ◽  
Author(s):  
Eleanor H. Z. Gourevitch ◽  
J. Roger Downie
Keyword(s):  
Body Weight ◽  
Pilot Study ◽  
Radio Telemetry ◽  
Nest Building ◽  
Tree Frog ◽  
Application Time ◽  
Breeding Behavior ◽  
Dense Vegetation ◽  
Laboratory Conditions

Evaluation of tree frog tracking methods using Phyllomedusa trinitatis (Anura: Phyllomedusidae). Investigating the behaviors of small, inconspicuous and cryptic animals can be helped by tracking their movements. The effectiveness of different tracking methods can be very dependent on behavior and ecology; radio-telemetry and thread bobbins have been widely used over a range of environments and taxa, but each presents problems. Phyllomedusa trinitatis is a tree frog found in Trinidad and Venezuela and has mostly been studied for its nest building and breeding behavior, but little is known about its behavior away from breeding ponds. This study aimed to identify the strengths and weaknesses, including impacts on the welfare of these frogs, of different tracking methods, thread bobbins and radio-telemetry, when used to track them in a dense rainforest environment. A pilot study found that fuorescent dyes were unsuitable for this species. Individuals were tested in laboratory conditions to determine the application time for each tracker and to test on this species the tracker 10% weight rule. The rule was found to be too restrictive for this frog; trackers up to 15% of body weight were used with no signifcant impacts on distances travelled. Frogs became lethargic when bearing trackers longer than two days, so we limited tracking in the feld to one overnight period. Of the 26 frogs tracked in the feld (nine radio-tags, 17 bobbins), 16 were successful (six radio-tags, 10 bobbins) and six untracked frogs were found in the feld during the day as controls. Bobbins were cheaper and allowed visualization of the detailed path taken, including substrates used, but caused more bruising due to entanglement, and individuals tracked with this method were less likely to return on following nights to the breeding ponds. Radio-tags had no threat of entanglement but were much more expensive and the signal was interrupted by the dense vegetation preventing some individuals from being found. There were no signifcant differences in the distances travelled by tracked or control frogs, from which we infer that these tracking methods did not impact signifcantly on movement. It appears that neither of these tracking methods work perfectly for Phyllomedusa in a densely vegetated environment, and that both incur welfare problems. Our study emphasizes the need to test out tracking methods on each species in each habitat.

Fictive locomotion and scratching inhibit dorsal horn neurons receiving thin fiber afferent input

2000 ◽  
Vol 279 (2) ◽  
pp. R394-R403 ◽  
Author(s):  
A. M. Degtyarenko ◽  
M. P. Kaufman
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Tibial Nerve ◽  
Dorsal Surface ◽  
Fictive Locomotion ◽  
Thin Fiber ◽  
Group Iii ◽  
Dorsal Horn Neurons ◽  
The Mean ◽  
Stimulation Of

In decerebrate paralyzed cats, we examined the effects of two central motor commands (fictive locomotion and scratching) on the discharge of dorsal horn neurons receiving input from group III and IV tibial nerve afferents. We recorded the impulse activity of 74 dorsal horn neurons, each of which received group III input from the tibial nerve. Electrical stimulation of the mesencephalic locomotor region (MLR), which evoked fictive static contraction or fictive locomotion, inhibited the discharge of 44 of the 64 dorsal horn neurons tested. The mean depth from the dorsal surface of the spinal cord of the 44 neurons whose discharge was inhibited by MLR stimulation was 1.77 ± 0.04 mm. Fictive scratching, evoked by topical application of bicuculline to the cervical spinal cord and irritation of the ear, inhibited the discharge of 22 of the 29 dorsal horn neurons tested. Fourteen of the twenty-two neurons whose discharge was inhibited by fictive scratching were found to be inhibited by MLR stimulation as well. The mean depth from the dorsal surface of the cord of the 22 neurons whose discharge was inhibited by fictive scratching was 1.77 ± 0.06 mm. Stimulation of the MLR or the elicitation of fictive scratching had no effect on the activity of 22 dorsal horn neurons receiving input from group III and IV tibial nerve afferents. The mean depth from the dorsal surface of the cord was 1.17 ± 0.07 mm, a value that was significantly ( P < 0.05) less than that for the neurons whose discharge was inhibited by either MLR stimulation or fictive scratching. We conclude that centrally evoked motor commands can inhibit the discharge of dorsal horn neurons receiving thin fiber input from the periphery.

Arachidonic acid stimulation of mucus production by rat gastric cultured cells

1987 ◽  
Vol 32 (8) ◽  
pp. 878-882 ◽  
Author(s):  
Akira Terano ◽  
Hideyuki Hiraishi ◽  
Shin'ichi Ota ◽  
Tsuneaki Sugimoto
Keyword(s):  
Arachidonic Acid ◽  
Cultured Cells ◽  
Mucus Production ◽  
Stimulation Of

Development of functional innervation in the second and third order auditory nuclei of the chick

Development ◽  
1988 ◽  
Vol 104 (4) ◽  
pp. 575-588
Author(s):  
A.G. Pettigrew ◽  
A.D. Ansselin ◽  
J.R. Bramley
Keyword(s):  
Auditory Nerve ◽  
Current Source ◽  
Dorsal Surface ◽  
Synaptic Activity ◽  
Direct Stimulation ◽  
Final Destination ◽  
Functional Connections ◽  
Auditory Nerves ◽  
Dendritic Fields ◽  
Stimulation Of

The neurones that constitute the auditory nuclei of the brainstem in the chick (nuclei magnocellularis, NM, and laminaris, NL) are generated between days 2 and 4 of incubation. These neurones migrate towards the dorsal surface of the brainstem over the next few days and reach their final destination at about day 9 of incubation. We have examined the development of functional connections between the auditory nerve and neurones in NM and between neurones in NM and NL in embryos from stage 34 (day 8 of incubation) using electrophysiological techniques and electron and light microscopy. The earliest extracellular recordings of electrically evoked field and spike potentials were made in NM with stimulation of the ipsilateral auditory nerve and in NL with stimulation of the ipsilateral NM at stage 35 (day 9). No activity could be recorded in NL with stimulation of the auditory nerve at this stage. By stage 37 (day 11), direct stimulation of the contralateral NM evoked responses in NL and by stage 38 (day 12) stimulation of the auditory nerves evoked stable field potentials in NL. These potentials changed polarity as the electrode penetrated NL in a direction that was perpendicular to the laminar arrangement of neurone somas and parallel to the dendritic axes of these neurones. In 18 of 26 analyses of current-source density in NL of 12 preparations between stages 38 and 40 there was a sink of current associated with synaptic activity at levels both above and below the source of current (cell somas) following stimulation of the ipsilateral auditory nerve. In the remaining analyses, and in all 15 analyses from preparations older than stage 40, stimulation of the ipsilateral input evoked only a single sink of current above the level of the cell somas. In all preparations from embryos at stage 38 and older, stimulation of the contralateral auditory nerve was associated with a single sink of current below the level of the cell somas. The axon projections to the ipsilateral NL from neurones in NM were examined using HRP labelling between stages 38 and 40. The presence of terminal fields of single axons in both the dorsal and ventral dendritic regions of the ipsilateral NL at these ages was confirmed. Furthermore, dense vesicles within synaptic terminals in both the dorsal and ventral dendritic fields could be identified in preparations at stage 36 following injection of HRP into NL and stimulation of the ipsilateral NM.(ABSTRACT TRUNCATED AT 400 WORDS)

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